"On behalf of the NetBSD Release Engineering Team, it is my pleasure to announce that the first release candidate for NetBSD 4.0 has been released," Liam Foy posted to the NetBSD -announce mailing list. The release has been a long time coming, first announced in August of 2006 by Jeff Rizzo, "NetBSD 4.0_BETA was branched on August 8, 2006 (UTC), and the beta-testing process has officially begun." Shortly after that, Charles Hannum, one of the NetBSD creators, posted an email self-described as a possible eulogy and calling into question the future of the NetBSD project. Updates regarding NetBSD 4.0 were posted in November and December of 2006 regarding delays resulting from two IRC hackathons which caused "a huge flurry of bug-fixing activity, which improved the quality of NetBSD-current a huge amount." This led to NetBSD 4.0 being rebranched from -current to preserve the large number of bug fixes that were made there.

The project's website maintains a comprehensive list of changes in NetBSD 4.0 as compared to the current stable 3.x branch. Liam continued in the release announcement, "we expect to release a second release candidate in about two weeks. Please help us test these release candidates as much as possible, to make sure NetBSD 4.0 will be a solid release.".